Do I need to create users in the containers? If so, what is the way to create shared user between all the containers?
If you want to run as a non-root user, you will need to create that user inside the containers. If you want to use a particular user id across multiple containers, the easiest solution is probably to create a base image that creates that user, and then build your application image on top of that.
Alternately, you can just run the appropriate adduser or useradd or whatever is appropriate as part of the build steps for each individual image.
Do I just chown to nobody? Do I chmod 777?
You probably don’t want to do either of these things. Either run your services as root, or arrange to create user and have files and directories owned by that user.